Leather-stretching device.



v .Patented Jan. 7, |902. J. CALDWELL.

LEATHER STRETCHING DEVICE.

{Applicaticn led Dec. 1. 1899.)

(lo Model.)

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UNITED STATES PATENT OFFICE.-

JOHN OALDIVELL, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO THE W. NOTT COMPANY, OF MINNEAPOLIS, MINNESOTA, A CORPORATION.

LEATHER-STRETCHING DEVI-CE.

SPECIFICATION formingpart of Letters Patent No. 690,397, dated January '7, 1902.

Application filed December 1, 1899.. Serial No. 738,820. (No model.)

To all 'whom t may concern:

' Be it known that I, JOHN CALDWELL, a citizen of the United States, residing at Minneapolis, in the county of Hennepin and State of Minnesota, have invented certain new and useful Improvements in Leather-Stretching Devices, of which the following is a specification.

My invention relates to devices for stretchio ing strips or divisions of leather-such as backs, sides, centers, &c.-to prepare them for use in the manufacture of belting. The

common practice in the preparation ofleatherV for belting is to sever the hides transversely x5 at the shoulder, trim the sides to straighten theedges, and cut the butts longitudinally into sides and backs or other divisions of desired widths, but leaving the rump ends of irregular shape. For holding such divisions 2o during the operation of stretching the colnmon practice is to clamp the ends to the proper members of a stretching-machine, and in order to prevent the slipping of the leather in the clamps under strong tension it is found 23 necessary to provide the contact-surfaces of the clamps with ribs or other irregularities, with the result of producing corresponding creases or irregularities in the clamped portions of the leather, which portions are generally unt for use in the, manufacture of belting and are cut ed as waste. Therefore the portions of leather at'the rump ends lying outside the clamps are not subjected to the stretching operation and together with 3 5 the creased portions are cut od as waste. vIn'- stead of such clamps nails have sometimes been employed for securing the ends of the leather; but whether clamps or nails were -used it has uniformly been the practice, so 4e far as I am aware, to secure both ends of the leather across its entire width before any part of the leather is subjected to tension, and when tension is then applied it is equal in degree and duration upon all parts of the leather-that is, the firmer and less yielding portions are stretched to the same degree or extent as the softer and less iirm portions. The result of such operation usually is that the firmer portions (those nearer the middle 5o of the hide) are stretched too much and the softer portions (those nearer the outer edges of the hide) are not stretched enough'. Such stretching does not serve to remove the warp or twist or buckle that hasbeen produced by the preliminary process of wetting and greasing and partly drying the leather.

The principal objects of the present invention are to 'provide simple and convenient means for securing the ends of the strips of leather in a way that will avoid the formation of objectionable creases in it, lessen the proportion of waste material, and enable the softer and harder portions to be stretched successively and to a different extent,as their variations of fiber may require to bring all parts to substantially equal hardness in the finished product. Such devices are illustrated in the accompanying drawings, in which*- Figure lis a plan view of a leather-stretching apparatus embodying my improvements and showing a side of leather in place thereon. Fig. 2 isa vertical longitudinal section, enlarged, of the same on the line @c n: of Fig. 1. Fig. 3 is a detail View from beneath the sliding head and a portion of the stretchingframe. Fig. 4 is a plan view of the fixed head, showing the straight end of the leather secured by nails driven through it into the wooden surface of the head. Fig. 5 is a similar view showing the leather secured by pins provided on the outer clamp-plate, and Fig. 6 is a sectional view on the line 1/ y of Fig. 5.

In such drawings the frame for supporting the leather-holding devices is composed of side bars l and cross-bars 2. The frame is provided with a fixed stretcher-head A and a slidable head B,to which the ends of theleather are secured. The latter head has suitable lateral extensions in ways 3 formed in the side bars for guiding its reciprocatory movements.

In use the frame is placed on a table or otherv support 4 with the ends of the side bars abutting the ends ofthe frame 5, which supports the power mechanism. The latter may consist of any of the usual means employed in like machines, and, as illustrated, may comprise gears 6, a screw 7, revolubl y connected to a cross-head 8, and rods 9, carried by the latter and provided with hooks IO for making connections with eyes 11,provid ed on the slid- IOC ing head B. The operation of the screw in either direction or its stoppage when desired should be under the control of an operator by means ot' a lever, hand-wheel, or other wellknown device, (not shown,) so 1hattl1e` degree of stretching of the leather may be regulated as desired by the operator.

The stationary and sliding stretcher-heads A and B are of similar construction and are formed of upper and lower boards l2 and 13, the grain of the former preferably running parallel with and of the latter transverse to the frame sides 1, and the boards are held in place between angular clamping-plates 14 and 15, the former plates being placed on the in-y ner and the latter on the outer edges of the boards. The lower boards are clamped between the vertical portions of the plates by bolts-16, and the upper boards are held in place by the horizontal flanges 17 of the plates 15 and the inclined flanges 18 of the plates 14, the upper boards being shaped to lit the space between the flan ges and the lowerboard. The upper boards may be removed and renewed when required by loosening the nuts On the bolts 16 and moving the clampingplates outward. The fixed head A may be secured in place by lateral bolts 19, extending through the frame sides and into or through the board 13. The lower edges ofthe boards 13 seat on lips or flanges 20,extending inward v oted to ears on the plate 14, with teeth on bars 22, attached to the frame sides.

For securing the straight end of a side or other division of leather C to the lixed or sliding head there is provideda series of permanent pins or tines 23, extending across the head at right angles to the sides of the stretcher-frame. These tines may be provided on the top flange 17 of the clamp-plate 15. The straight end portion of the leather is laid on the tines and secured by pounding with a mallet or other tool to force the tines through the leather.

Itis desirable that the face of the flange 17 that carries the tines be flush with the surface of the wood of the stretcher-head, so that when the leather has been secured to the tin es itslowersurface will be quite close to the Wood of the head. The purpose of this is to enable nails to be driven through the leather into the wood near the tines, as indicated in Fig. 5, tojsupplement the tines in holding the Yleather whenever it is found that they are in- Sufficient alone to properly hold the leather. It'not infrequently occurs that a portion of the margin engaged by the tines is not tough enough to withstand the tension. of the machine,and the tines begin to tear it, and when this is observed by the operator he is enabled to prevent further tearing by driving a few nails through the leather into the wood in advance of the tines. The tines may be made to engage the leather quite close to its edge, and will usually be found sufficient to hold it against the severe tension of the machine.

To secure the rump end (orother irregular end) of the leather to the sliding head (or to the iXed head, if preferred, for the relative positions of the heads A and B are obviously a matter ofl choice) nails 25 alone are used, and they may be driven near the edge and in courses conformable to the irregularities of the outline of the leather. By so doing all portions of the leather may be subjected to the stretching operation, and the portion that would lie outside the straight line a clamp would occupy is, equally with other portions, stretched and tted for use for belting. In driving the nails their heads should be allowed to stand u p from the leather suiciently to enable them to be readily pulled out with a claw-hammer or like tool.

In securing the irregular end of the leather a portion of its margin at the shorter and softer side is first nailed to the head, and the longitudinal section thus secured is rst stretched until it is thought to be of about the hardness of the next adjoining portion, and the latter is then nailed fast and stretched, along with the portion rst engaged, until the two portions are thought to be equal in hardness to the next adjoining portion. The latter is then also secured and stretched along with the others, and so on, until each succeeding portion has been successively attached and stretched with preceding portions, and

when all portions have been secured they may be stretched as a whole as much more as the nature of the body of leather' may require. As the leather of different hides varies considerably in thickness, firmness, and capability of stretching, the Width of the sectional portions to be successively engaged and stretched and the extent to which preceding portions should be stretched before succeeding portions are engaged must be left to be determined by observation and manipulation in the treatment of each body of leather.

In the operation of stretching the leather it is desirable to have its body portions lie on cross-bars 26, that rest and may be made to slide on the side pieces l, and which the operator may shift from time to time toward or away from the ends or to inclined positions, as indicated by dotted lines in Fig. 1, as in his judgment may be desirable to compensate for unequal stretching of the edges or other portions of the leather.

Having described my invention, what I claim is- 1. The combination witha stretcher-frame, of a head having a body of wood heldin place by clamp-plates, one of which plates is provided with a series of permanent tines in close arrangement and extending in a 'row transversely to the sides of the stretchervframe, substantially as set forth.

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head composed of clamping-plates having which is at a right angle and the other at an suitable flanges, aboard secured between the obtuse angle to its plate, boards tted belower portions of the plates by bolts,'aud a tween such plates, and means for clamping removable board held in the space between the plates to them, substantially as set forth.

5 the lower board and the upper flanges of the In testimony whereof I have hereunto set I5 plates, for the purpose set forth. my hand this 27th day of November, 1899. 3. In a leather-stretching machine, the oom- JOHN CALDWELL.

bination with astreteher-frame, ofastretoher- In presence ofhead consisting of clamping-plates at front P. H. GUNOKEL,

1o and rear and provided with flanges one of i M. F. HARRISON. 

